←back to thread

Why does the chromaticity diagram look like that?

(jlongster.com)
276 points samwillis | 1 comments | 26 Jul 24 18:19 UTC | HN request time: 0.204s | source
Show context
carlosjobim ◴[26 Jul 24 22:16 UTC] No.41082809[source]▶
I think the explanation is simple: Color is light and it is linear going from ultraviolet to blue to green to yellow to red to infrared. It's just a line.

In physical reality, there exists no purple light. Our minds make up all the shades of purple and magenta between blue and red when our eyes receive both red and blue light.

So in order to include the magentas, you need to draw another line between blue and red. Meaning you have to bend the real color line. And that's what we see in the chromaticity diagram.

replies(3): >>41083084 #>>41084320 #>>41093708 #
1. mncharity ◴[27 Jul 24 03:51 UTC] No.41084320[source]▶
> Color is light

For an ELI5 on a "maybe teach color better by emphasizing spectra?" side project, I went for hard disjointness on "color" vs "light". Distinguishing world-physics-light from wetware-perception-color. Writing not "red light", but "\"red\" light". So physical spectra were grayscale, on nm and energy. Paired with perceptual spectra in color, on hue angle and luminosity. And both could be wrapped around a 3D perceptual color space (tweening the physical spectra from nm to hue). Or along a 2D non-primate mammalian dichromat space, to emphasize the wetware dependence. Misconceptions around color are so very pervasive, K-graduate, that extreme care for clarity seems helpful.